Totally agree that proofs are more useful than opinions.
Let's do one.
You refer to the following as a theorem of probability:
If the probability of a favorable outcome after one trial is p, it will take on average 1/p trials to obtain it.
Fair enough. Let's see if we can prove it, at least within the context of this puzzle.
After showing say a '2' on the first roll we want a 1, 3, 4, 5 or 6 to show next.
There are 6 possible outcomes; 5 are favorable.
If we were to roll the die 6 times we would expect 5 favorable results [5 of 6 equally likely events are favorable].
Number of trials: n=6.
Number of favorable outcomes: f=5.
There are two things we can now say:
The probability of a favorable outcome = f/n = 5/6
The number of trials for a favorable outcome = n/f = 6/5.
The first quantity is p. The second quantity is 1/p.
Thus, if the probability of a favorable result after one trial is p, then it takes 1/p trials to expect the favorable result.